The prosecutor told a judge that Affleck's character is spared prosecution in the movie after being told a person cannot be charged for an accidental crime.

Only days after the film won two Academy Awards, a fire was reported at the Franklins' home in Guilford - about 180 miles (290km) north of New York City.

"The victim was badly burned," Mr McBride said, according to a transcript of proceedings as the couple appeared in Chenango County Court on Friday.

"Because of the damage to the body by the fire, the pathologist is not able to determine the cause of death," he added

However, the boy did not have smoke or soot in his mouth or airway, which would have indicated he had been alive when the fire broke out, said officials.

Image copyrightStudio CanalImage caption
Casey Affleck won a Best Actor Academy Award for his role as a grief-stricken father

According to the prosecutor, the boy had special needs and suffered from chronic incontinence.

Mrs Franklin, 33, had complained on Facebook about the toll taken by caring for Jeffrey, whom the couple adopted in around 2012.

"There was a very big strain in the family relationship because of Jeffrey's special needs and that this defendant was complaining on Facebook about the strain that that was putting on her," said Mr McBride.

Mrs Franklin - who is currently pregnant - told investigators that she had visited two shops looking for medication that night.

But the prosecution says evidence shows she did not go to the store aisles where the drug was stocked.

Mr Franklin, 35, said he had been outside chasing his dogs when the fire occurred.

But while Affleck won a Best Actor Oscar for his role as a grief-stricken father in the movie, investigators did not find Mr Franklin so convincing.

Mr McBride said police found the husband to be "very calm, cool, collected" as they arrived at the home.

He allegedly "pointed to the room where Jeffrey was lying and the defendant had no physical injuries from any attempt to try to save him".

Mrs Franklin's lawyer told the court she was innocent until proven guilty.

He added the state was "charging her with murder without even knowing what caused the death".

If convicted, the couple faces up to 25 years in prison.

Nearly $11,000 (£8,700) raised by a GoFundMe campaign was returned to donors after criminal charges were filed, according to WBNG News.